Statistics · Ch 1 — Collection of Data
Secondary Data and Its Sources
Secondary Data and Its Sources
Secondary data is data that already exists — it was collected by some other person, organisation, or agency for their own purpose, at an earlier time, and the present investigator simply makes use of it. Government publications, published reports of companies, newspapers, and international agency statistics are all common sources of secondary data.
Secondary data is generally faster and cheaper to obtain than primary data, since the work of collection has already been done by someone else — but it comes with an important responsibility: it must always be critically examined before use, because it was collected for a different purpose, at a different time, possibly using a different definition of the same term, or from a different geographic scope, than the present study needs.
Checks before using secondary data
A careful investigator checks secondary data on at least these points before relying on it:
- Suitability — does it actually fit the objective, area, and time period of the present study?
- Adequacy — does it cover the topic in sufficient scope and detail?
- Reliability — was it collected by a competent, unbiased, and reputable source, using a sound method?
- Comparability — were the same definitions, units, and classification used, so it can be legitimately compared with the present study's own figures? …
Data that already exists — originally collected by some other person or agency for their own purpose — and is merely reused by the present investigator, rather …
The necessary check of secondary data for suitability, adequacy, reliability, and comparability before it is used in a new study, since it was originally gath …